The stored energy and the energy release during SPD (superplastic deformation) ofa Zn-5Al alloy were studied. The alloy after rolling process gains more stored energy, and the as-rolled specimen can obtain maximum elongation and minimum flow stress without hot holding treatment before SPD. Experimental results show that stored energy release process is along with SPD process and is also an impetus to SPD. The as-rolled Zn-5Al alloy has 48 J/mol stored energy which was measured with DSC (differential scanning calorimeter) and conforms well to the calculated value. The as-rolled Zn-5Al alloy after SPD with an elongation of 2 500% releases 112 J/mol stored energy. Analysis shows that the strain rate is in direct ratio to the rate of stored energy release.